class MinStack {
public:
    /*
    * @param a: An integer
    */
    //MinStack(int a) {
        // do intialization if necessary
    //}

    /*
     * @param number: An integer
     * @return: nothing
     */
    void push(int number) {
        // write your code here
        stackNum.push(number);
        if (minStack.empty()) {
            minStack.push(stackNum.top());
        } else {
            if (minStack.top() <= stackNum.top()) {
                minStack.push(minStack.top());
            } else {
                minStack.push(stackNum.top());
            }
        }
    }

    /*
     * @param a: An integer
     * @return: An integer
     */
    int pop() {
        // write your code here
        int popNum = stackNum.top();
        stackNum.pop();
        minStack.pop();
        return popNum;
    }

    /*
     * @param a: An integer
     * @return: An integer
     */
    int min() {
        // write your code here
        return minStack.top();
    }
private:
    stack<int> stackNum;
    stack<int> minStack;
};